1. Field of the Invention
The invention is directed to an internal combustion engine and engine braking device having a valve control unit that holds an exhaust valve in an intermediate position when activated.
2. Description of the Related Art
An internal combustion engine of the type mentioned above is described, for example, in EP 1 526 257 A2. The engine braking device in this internal combustion engine is a combination of an engine exhaust brake and a compression release brake, also known as EVB (Exhaust Valve Brake). A hydraulic valve control unit is installed on one side in a valve bridge that actuates two exhaust valves simultaneously. The supply of oil to the valve control unit is carried out by the existing oil circuit in the internal combustion engine. Separate adjustment screws are provided for compensating valve lash in the exhaust valves and are used to adjust the valve lash when assembling the engine or afterwards at regular servicing intervals. This is uneconomical.
In the event that excessive valve lash is unintentionally adjusted by assembly or servicing personnel, chattering noises will result between the rocker arm and valve bridge and there is a risk that the valve train will be damaged. Further, the exhaust valves do not open sufficiently, so that a complete exchange of gas is not ensured. If insufficient valve lash is adjusted, there is a risk that the valves will not close completely in the hot state and will accordingly burn out.